Broad-band omnidirectional spherical lens antenna with rotating amplitude modulationpattern



March 9, 1965 D. F. BOWMAN 3,173,143

BROAD-BAND OMNIDIRECTIONAL SPHERICAL. LENS ANTENNA WITH ROTATING AMPLITUDE MODULATION PATTERN Original Filed June 17, 1958 4 Sheets-Sheet l March 1965 D. F. BOWMAN 3,173,143

BROAD-BAND OMNIDIRECTIONAL. SPHERICAL. LENS ANTENNA WITH ROTATING AMPLITUDE MODULATION PATTERN Original Filed June 17, 1958 4 Sheets-Sheet 2 March 1965 D. F. BOWMAN 3,173,143

BROAD-BAND OMNIDIRECTIONAL SPHERICAL. LENS ANTENNA WITH ROTATING AMPLITUDE MODULATION PATTERN Original Filed June 17, 1958 4 Sheets-Sheet 3 March 9, 1965 D. F. BOWMAN 3,173,143

BROAD-BAND OMNIDIRECTIONAL SPHERICAL LENS ANTENNA WITH ROTATING AMPLITUDE MODULATION PATTERN Original Filed June 17, 1958 4 Sheets-Sheet 4 4 Mg/l I t L l4l "/0 1:1

I38 mu 3" lfl-Il/LJ'E [58 4W! United States Patent Ofi ice Patented Mar. 9, 1965 3,173,143 I BROAD-BAND OMNIDIRECTIONAL :SPHERICAL LENS ANTENNA WITH ROTATING AMPLI- TUDE MODULATION'PATTERN David F. Bowman, Wayne, Pa assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., 2 corporation of Pennsylvania Original application June 17, 1958, Ser. him-742,646, now Patent No. 2,990,545, dated June 27,1961. Divided and this application June 15, 1961, Ser. No. 117,235

- 12 Claims.- (Cl. 343--754) 1 This is a division of application Serial No. 742,646 filed June '17, .1958, now U.S. Patent No. 2,990,545.

This invention relates generally to directional transmitting antenna, and more particularly relates to novel antenna for transmitting the directional radio pattern for theradio navigational system known as Tacan.

The Tacan system has been developed in recent years, initially for military aircraft, being'an abbreviation of tactical air navigation. It operates in the UHF spectrum, being assigned the range 960 me. to 1215 mc. The low band Tacan range is 960 to 1024 mc.; the high band, 1150 to 1215 me. The intermediate band 1024 to 1.150 me. is used for interrogation of the Tacan station by an aircraft for distance determinations.

The Civil Aeronautics Administration is setting up a system of transmitting stations combining T acan with civilian VHF omnirange or VOR. The latter system is known as Vortac. One of the new requirements for the Tacan transmitter antenna is that it be directly adaptable to efficiently transmit its patterned signals over any frequency in either of the Tacan high or loW bands. The present invention provides novel antenna systems with broad-band characteristics to accomplish this feature.

Another important Civil Aeronautics Administration requirement is to have the tranmitted Tacan pattern be effective over an elevation range from the horizon to at least 60 above the horizon. Such wide elevation coverage has been unattainable with prior antennae. Further, the new Tacan transmitted signals are to be of higher gain than heretofore, namely, to be 'six db over that of an isotropic source. The antenna systems of the present invention accomplish these important and desirable objectives.

In accordance with my invention, I utilize a dielectric sphere known as a Luneberg lens, and provide multiple or infinite point sources of the radio Waves to be radiated from a circular path on the sphere. The result is 360 horizontal radio pattern of I general toroidal form. I further incorporate therein modulators to shape the toroidal form with fundamental and nine lobed modulations to constitute the characteristic Tacan pattern. Rotation of the modulated point sources at 900 r.p'-.m. about the sphere results in the Tacan signal transmission intercepted at 15 and 135 cycles per second.

It is accordingly a primary object of the present invention to provide a novel transmitter antenna incorporating a dielectric sphere with multiple radio point source thereabout to produce a generally toroidal pattern. 1 Another object of the present invention is toprovidea novel Tacan antenna utilizing a dielectricsphere to transmit a Tacan pattern with a gain at the.0' to elevation angles of six db over an isotropic source.

A further object of the present invention is to provide a novel antenna incorporating a dielectric sphere to trans rnit a generally toroidal 360 radio pattern withielfective signal strength from horizon to at least 60 above the horizon.

Still another object of the present invention. is to provide a novel antenna system capable of efiiciently transmitting a Tacan radio array at any frequency over the whole UHFTacan band.

Still a further object of the present invention is to provide a novel Tacantransrnitter antenna that'is efiicient, rugged and capable of long-time uninterrupted operation.

The above'and further objects of the present invention will become more apparent from the following description'of exemplary embodiments thereof, illustrated in the drawings, in which:

FIGURE 1 is a polarrep'resentation of an idealized radio Tacan pattern in a singleelevation plane.

FIGURE 2 isa polar representation of theantenna radiation pattern in a single azimuth plane as modulated with nine lobes.

FIGURE 3 is a polar'represe'ntation of'thenntenna radiation pattern in .a single azimuth plane as modulated by the fundamental frequency.

FIGURE 4 is a polar representation of the composite antenna radiation pattern per FIGURES 2 and 3.

- FIGURE 5 is a diagrammatic showing of the operation of a Luneberg lens with a single radio point source.

FIGURE 6 is a curve illustrating the relative" signal strength of the Luneberg lens beam at angular deviations from the normal direction.

FIGURE 7 is a polanrepresentation of the beam emitted from the lens of FIGURE 5.

' FIGURE 8 is a perspective schematic diagram of the multiple or infinite radio point sources for the spherical lens, in'a'ccordanc'e with my invention.

FIGURE 9 is a perspective 'illustration-ofan exemplary means-for generating the radio point-sources in the lens or FIGURE 8.

FIGURE l0is a cross-section view through a spherical antenna arrangement utilizingthe signal feed means of FIGURE 9.

FIGURE 11 is a plan viewof the signal feed system of FIGURES 9 and 1t) incorporating modulator elements.

FIGURE 12 is an enlarged cross-sectional view through the line 12-12 of FIGURE 11, illustrating an exemplary modulator element.

FIGURE 13 is a diagrammatic showing of a-modified spherical lens antenna in accordance with my invention.

FIGURE 14 is apolar representation in a -single elevationplane of the radiation pattern of the antenna of FIGURE 13.

FIGURES 15, '16 and 17 are illustrations of further forms which my antenna may assume in practice.

' FIGURE 18 is a polarrepresentation in a single azimuthal plane of the radiation pattern ofthe antenna of FIGURE 17.

FIGURES l9 and 20 are schematic showings of alternat'e radiosignal feed positions with: respect to the antenna hereof.

FIGURE 21 is a plan View of the trigger disc of the pulse generator of the invention system per FIGURE 22.

FIGURE 22 is a cross-sectional view vertically through a complete antenna structure in accordance to the present invention.

In FIGURE 1, I have represented inp'olar form the new Civil-Aeronautics Administration requirements as to the radiated Tacan pattern in an elevation plane; Radial distance from the'origin represents'signal field strength as a function of elevation angle. A typical pattern 24 is shown enclosing the minimum requirement. pattern. The minimum requirement pattern isoutlined starting at the origin bythe horizontal abscissa to point 25 corresponding to six db gain over an isotropic source, byanarc 26 to point 27, 5" above the horizon by cosecant line 23 parallel to the horizon to point 29, 60" above the horizon and by radial line 30 to the origin.

The basic Tacan pattern comprises a uniform nine lobed modulation 31, an: as showii in FIGUREIZ. The lobes 31, 31a are specified to be greater in amplitude 3 than the carrier level, represented in FIGURE 2 by the broken uniform circle 32 with center 0. The troughs 31a are specified to be 21% less in amplitude than the carrier level.

The Tacan pattern also requires a fundamental modulation as represented by FIGURE 3. This may be the essentially circular pattern 33, having its center displaced from reference center c whereby in amplitude the peak of curve 33 is 21% greater and the valley of curve 33 is 21% less than the radius of the reference circle 32.

The Tacan 360 radiation pattern is represented in FIGURE 4 by polar curve 35, in a typical azimuth plane, with point 0 as the origin. Curve 35 is the composite fundamental and nine lobe modulation of the basic omnidirectional uniform 360 radio pattern represented by basic circle 32. The pattern 35 is rotated about its origin at c to elfect the Tacan system results. The antenna of the present invention produces a rotating spatially modulated Tacan pattern as represented by the FIGURES 1 through 4.

FIGURE illustrates the action of a Luneberg lens 40 on a single radio point source P. The Luneberg lens, as known in the art per se, is a sphere of dielectric material in which the dielectric constant varies gradually with the radius from center c. It is densest, namely of the value 2.0 at the center, to least dense at the surface, namely with a value of 1.0. In such a sphere 4f the index of refraction n of the radio waves 41 passing therethrough varies with the normalized radius according to the formula n= /2 \2.

At the microwave frequencies utilized in Tacan transmission, namely, of the order of 1,000 megacycles, the lens 40 produces a uniform emergent radio beam 41. Thus, any circular aperture at or near the lens, represented at A, along beam 42 will have a radio pattern of uniform phase and uniform amplitude.

FIGURE 6 represents the relative amplitude or signal strength 2 of a beam such as 42, when measured at angular deviations 0a with respect to the beam (42) axis (fairly remotely from lens 40). It is noted, as FIGURE 6 curve 43 shows for a horizontal beam (42), in that there is an eleavtion signal variation from the peak value of e at 44 on the beam axis 45. The main lobe of curve 43 in elfect reaches the zero level at points indicated at 46, 46 which, depending upon the sphere (40) diameter and other factors may occur, for example, at +6, +8, etc.

It is also to be noted that minor lobes 4747, 48-48 and 49--49 are also represented in curve 43 for greater elevation deviation from a horizontal beam (42).

FIGURE 7 shows a polar curve 50 in elevation for a horizontal beam (42) from a spherical lens (40). The main lobe 51 extends uniformly above (52) and below (53) the beam axis 54. The minor lobes 55, 56 and 57 correspond to those indicated at 47, 48 49 in FIGURE 6. The relative signal strength e is determined by the intersection of curve 50 with the elevation line 58 at on degrees from a vehicle V such as an aircraft.

An important feature of my invention is to utilize a radio microwave lens such as a Luneberg sphere and apply simultaneously thereto an infinite number of radio point sources along a circular region thereof.

FIGURE 8 diagrammatically represents the lens 60 with the multiple or infinite radio point sources P, P along the equatorial circle 61. The lens center is at c, and its zenith at line 62.

The 360 array 61 of point sources P, P produces a toroidal pattern of an otherwise linear beam (42) due to a single point source noted above in connection with FIGURE 5. For uniformly phased and equal amplitude radio point sources P, P along circle 61, there results a symmetrical toroid pattern having a common vertical polar configuration along any elevation plane. Means are provided by my present invention to compositely modulate and rotate such uniform toroid patterns to effectuate 4 the requisite Tacan specifications described in connection with FIGURES 1 through 4 hereinabove.

FIGURE 9 is a perspective illustration of a uniform continuous or infinite point source feed or line for the microwave lens hereof. This feed or line system comprises two spaced metal discs 62, 63 fed by a center coaxial transmission line 64. A uniform axial radio source is projected by the transmission discs 62, 63 as indicated by radial lines 65, 65. Rotation of the disc array 62, 63 as indicated by arrow a effects a direct spacial rotation of the source pattern 65.

FIGURE 10 is a cross-sectional view through a simplified version of the invention Tacan antenna. The dielectric sphere 70 is of the Luneberg type with radial dielectric constant change, as described in connection with lens 4%) of FIGURE 5. Two discs 71, '72 are arranged horizontally along the diameter of sphere 70. A coaxial transmisison line with outer conductor 73 and inner conductor 74 couples to the opposed discs 71, 72 to feed a source of radio signals s to discs 71, 72.

The signals from source s are indicated as moving to the discs 71, 72 by arrow b, and then to radiate across the discs to their perimeters as indicated by arrows d, d as in the manner of FIGURE 9. The perimeter region of each disc 71, '72 preferably, though not necessarily, extends beyond the surface of lens 70. A horn reflector band 75 surrounds the periphery of discs 71, 72 to reflect the incident radio signal waves back to the lens 70 along the sphere. This reflection by band 75 effects the infinite radio point sources along a circular path of sphere 70 in the manner of FIGURE 8.

The reflector 75 is trough-shaped with a cross-section corresponding to a horn radiator. Horn reflector band '75 has a central flat region 76 constituting the reflector section oposite the signal emergent region of discs 71, 72, and two angular regions 77, 78 constituting the horn walls. Properly matched construction will produce substantially total transmission into the lens as indicated by arrow e with negligible reflection back into the narrowly spaced discs 71, 72 and with negligible undesired transmission, for example as shown by arrow 7". An efficient radio transmission system, with low VSWR is thus effected, providing the continuous point source band about lens 70. A Tacan type toroidal pattern results.

A series of beam modulator elements 80 are provided along the transmission discs '71, 72. Elements 80 modulate the otherwise azimuthally uniform toroidal beam emanating from lens 70 with the multiple lobes in accordance with FIGURE 4. An exemplary modular ele ment 80 is a bolt 89 mounted between discs 71, 72 in the radial path of a portion of the radio waves therebetween.

FIGURE 11 is a plan view of the disc assembly 71, 72, showing the top disc 71 and the multiple lobe modulator elements 80. Nine elements 80 produce nine uniform lobes (31). The desired amplitude of the lobes is determined by suitable radial spacing of the elements 80 on discs 71, 72, their diameter, and their metal composition, as will now be understood by those skilled in the art. A tenth modulator bolt 81 is located closer radially to center c of discs 71, 72 and constitutes the fundamental modulator for the lower frequency, corresponding to curve 33 of FIGURES 3 and 4.

FIGURE 12 illustrates an enlarged cross-section of modulator bolt 80 having nut 82 set between discs 71, 72.

For maximum utilization of the emitted signal strength, and also to better meet the six db gain requirement, the radio transmission discs are moved below the equatorial area of the spherical lens.

FIGURE 13 illustrates lens 85 with transmission discs 86, 87 set below the equatorial diameter 38. The rim reflector 89 surmounts the projecting periphery of discs 36, S7. The coaxial signal s feed line 90 suitably couples with discs 86, 87 through a suitable matching transformer. The coaxial transmission line 943 is shown extending along the zenith diameter and above the disc plates 86, 87 to counter-balance the presence of the coaxial transmission line in the lens. It is noted that for Tacan operation, the modulator transmission disc combination is rotated about its zenith axis, along a. The lens 85 and reflector '89 are preferably stationary. The reflector 89 is advantageously supported on lens 85.

FIGURE 14 illustrates in polar form the upward tilt effected by the lowering of transmission discs 86, 87. The below horizon area 92 of curve 91 is reduced as compared to area 53 of FIGURE 7. Further, the elevation line intersection point 94' is increased in gain to better meet the requisite six db. The curve 91 peak is shifted close to the 5" line 94, though not necessarily on it.

FIGURES l5 and 16 show alternate forms for the lowering of the transmission circumference to eflect the upward beam tilt as per FIGURES 13, 14. The lens 11111 of FIGURE has two spaced conical metal members 101, 102, with a central coaxial feed line 103-. The reflector band 104- for lens 1% is shown as flat. This per mits the cone peripheries to remain interior of sphere 100. In sphere 105 of FIGURE 16, the two conical metal members 1116, 107 have a common apex position, as at center 0. They are fed by line 1&8. A trough horn-type reflector band 109 is used therefor.

Another important feature of the invention antenna is to be effective to the 60 elevation line per FIGURE 1. This requires a smoothing in of the lobes 95, 95 of FIG- URE 14 polar curve and of the nulls between lobes as indicated in FIGURE 18 at shaded area 1211. Thus, signals are radiated about the 360 toroid pattern to the 60 altitude with minimum cosecant 121 magnitudes maintained.

In FIGURE 17 is shown one form of the antenna hereof which smooths in the lobes 95. This antenna comprises a lens 110 of the Luneberg type with selected areas of different dielectric configuration. The modulator transmission plate array shown is with spaced cones 111, 112, and horn rim reflector 113. In the upper section of lens 110, is a conical or other suitably shaped region 114 of greater dielectric constant material than that generally present in a Luneberg lens. In the lower lens section, there is a conical region 115 of material having a generally lower dielectric constant than present for a Luneberg lens.

The result of the denser dielectric region 114 and lighter dielectric region 115 in sphere 111i is to change the minor lobed polar pattern, see 95, 95 in FIGURE 14, to a smoothed-in area indicated irregularly as 1211 in FIG- URE 18. This causes a continuous cosecant 121 relation as desired. Only the upper section of curve 122 is shown in FIGURE 18. The lower minor lobe polar portion is not significant in the Tacan display.

Other methods and arrangements may be used to effect the smoothing of lobes 5 5 (FIGURE 14) into toroidal area 120 (FIGURE 18). For example, the horn section of reflector (89 of FIGURE 13) may have its upper portion tilted at an angle away from sphere (85) to tilt or modify the phase front of the energy emerging from the horn reflector. Alternatively, the shape of either the upper or the lower section of the sphere (as at 85) and the dielectric constant within this section may be progressively altered to effect such smoothing in (1211) of the lobes (95).

While I have above illustrated the invention with the multiple radiopoint sources at or reasonably close to the surface of the microwave lens, these may be different if the dielectric constant is varied within the lens in the proper manner as well known in the art.

FIGURE 19 illustrates these point sources represented by P remote from lens 125. The resultant beam at aper ture A is uniform as required. Also, the radio point sources, represented by P" in FIGURE may be well 6 within the lens 126. The resultant beam at aperture A" is uniform.

A physical assembly of a Tacan antenna in accordance with my invention hereof is illustrated in vertical crosssection in FIGURE 22. The lens comprises two hemispheres 131, 132 of dielectric material. The practical radial variation of the dielectric constant of hemispheres 131, 132, in the Luneberg lens manner already described, is understood by those skilled in the art and is not detailed.

The upper hemisphere 131 has its center 0 spaced above the center 6 of the lower one 132. Open regions 133, 134 are formed between hemispheres 13-1, 132 to contain the rotating modulator transmission discs. The hemispheres 131, 132 are suitably fastened together by hardware 135, 136. The assembly is supported in a dielectric support cone 137 on frame 138 mounted on base 139.

The rotatable speed transmission metal discs 140, 141 have a firm foam dielectric layer 142 therebetween for composite support. The discs 1411, 141 are signal fed by and secured with coaxial transmission line 143, 144. Inner conductor 143 is connected to upper disc 14% by screw 145 and transformer sleeve 146. The outer conductor 144 connects by bracket 147 to lower plate 141. Outer conductor 144- is rotatably supported by roller bearings 143, 149.

The coaxial line 143, 144 extends through hollow shaft motor 151 The outer line 144 has a reduced diameter section 144 that is rotated by motor 151 and rotates discs 1411, 141 at 900 r.p.m. Discs 140, 141 have slab modulator elements 151, 151 to perform the results of bolts 80 of the other modifications described above. The ring reflector 152 is fiat as in FIGURE 15. A motor speed regulator is preferably employed to stabilize the rotation at requisite uniform speed. A sine wave generator 152, a pulse generator 153 and rotary electrical line coupler 154 are mounted beneath motor 151 The pulse generator 153 uses a disc 155 having elements 156 to effect the Tacan signal triggering.

The foam dielectric between the rotating radio transmission discs 14@, 141 has no electrical function. Its dielectric constant is thus kept low, such as 1.05. A firm foam layer of styrene is suitable. The pulse generator 153 and the sine generator 152 are connected to the Tacan electrical and electronic equipment (not shown), in the usual manner. The pulse generator 153 comprises a disc 155 of dielectric material with nine metallic memhere 156 spaced near its periphery 40 apart.

FIGURE 21 shows this arrangement. Disc 155 is secured to the rotating central transmission line at hub 157. The rotating trigger members 156 coact with the station ary yoke 15% to effect the identifying timed pulses for the distance measurement determinations of the moving vehicle. The fundamental frequency triggering is performed by passage of member 159.

The basic microwave signal to be modulated andbroadcast by the antenna system hereof is fed by a coaxial transmission line into the input of rotary coupler 154. The radio signal, at the selected Tacan broadcast frequency, is thus fed to internal rotating coaxial cable 143, 144- through the coupler 154. Suitable matching transformations are -maintained tothe coupler 154, through the motor with the line 143, 144, and on to the rotating discs. The discs rotate unhindered in the clear space set thereabout within lens 131 The antenna system of my invention is not frequency sensitive over the Tacan microwave band, and accordingly one basic construction can be. used for all Tacan and Vortac installations, regardless of the frequency selected to transmit. The radial distance of the modulator elements 1% may be shifted in some cases, before installation, for some selected frequency region. 'P're-drilled series of openings for this purpose may be provided.

In a physical embodiment of the invention antenna, a

Luneberg-type sphere was used, 18" in diameter. The rotatable radio transmission discs were located below the sphere center and coaxial with its zenith, being 26" in diameter to project beyond the sphere. These discs were spaced A interiorly.

A horn-sectioned reflector ring surrounded the projecting periphery of the transmission discs, with an outer circumference of 27". Thus, the outer horn rim was /2" from the disc periphery. The reflector base opening was about 4 across, and supported on the sphere. The modulator bolt elements were mounted at a radius of 8 /2" from the center of the discs; with the fundamental modulator, at 2" radius.

While I have described my invention in connection with several exemplary embodiments, modifications and variations thereof may be made without departing from the broader spirit and scope of the invention, as described in the following claims.

I claim:

1. A transmitter antenna of the character described comprising a radio Wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying impressed signal energy about a 360 segment of said lens, motor means for continuously rotating said transmission structure, and means electrically coupled to said radio transmission structure for applying radio signal energy thereto to eifect a 360 radiation pattern of transmission or" the signal energy about said lens, wherein the microwave lens is generally spherical in shape, rotatable transmission structure being comprised of a pair of opposed metallic plates supported within the lens and the spaced plates being of a greater radial extent than the sphere segment in which they are positioned and project to outside of the sphere.

2. A transmitter antenna of the character described comprising a radio wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying impressed signal energy about a 360 segment of said lens, motor means for continuously rotating said transmission structure, and means electrically coupled to said radio transmission structure for applying radio signal energy thereto to elfect a 360 radiation pattern of transmission of the signal energy about said lens, the 360 segment being substantially in a horizontal plane and the rotatable radio transmission structure being comprised of a pair of opposed metallic plates supported within the lens and the opposed plates are in the form of cones.

3. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported within said lens for applying signal energy about a 360 segment or" the lens, motor means for continuously rotating said transmis sion structure, means for applying radio signal energy to the interior rotatable radio transmission structure, and means altering the said basis dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher altitude angles.

4. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported within said lens for applying signal energy about 360 segment of the lens, motor means for continuously rotating said transmission structure, means for applying radio signal energy to the interior rotatable radio transmission structure, and means altering the said basis dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher altitude angles,

5 said specific region being in the upper section of the lens in an inverted conical shape with its apex near the lens center and its base intersecting the zenith, and composed of dielectric material of greater dielectric constant than that of the lens material surrounding the region.

5. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported within said lens for applying signal energy about a 360 segment of the lens, motor means for continuously rotating said transmission structure, means for applying radio signal energy to the interior rotatable radio transmission structure, and means altering the said basis dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher alttiude angles, said spcci 1c region being in the upper section of the lens in an inverted conical shape with its apex near the lens center and its base intersecting the zenith, and composed of dielectric material of greater dielectric constant than that of the lens material surrounding the region, further including a second conical region arranged mirror-symmetrically below said specific region and composed of dielectric material of smaller dielectric constant than that of the lens material surrounding it.

6. A transmitter antenna of the character described comprising a radio Wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying increased signal energy about a 360 segment of said lens, motor means for continuously rotating said transmission structure, and means electrically coupled to said radio transmission structure for applying radio signal energy thereto to eflect a 360 radiation pattern of transmission of the signal energy about said lens, said 360 segment being substantially in a horizontal plane in which the rotatable radio transmission structure is comprised of a pair of opposed metallic plates supported within the lens, said spaced plates being of a greater radial extent than the sphere segment in which they are positioned and project to outside the sphere, and in which the means for applying radio signal energy to said opposed metal plates comprises a coaxial transmission line arranged along the zenith diameter of the lens and secured to the central region of said plates through a matching transformer, further including an extension of said coaxial transmission line along the zenith diameter above the metal plates to counterbalance the presence of the coaxial transmission line in the lens.

7. A transmitter antenna of the character described comprising a radio wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying signal energy about a 360 segment of said lens and means for applying radio signal energy to said radio transmission structure whereby a 360 radiation pattern is transmitted about said lens, said microwave lens being gen erally spherical in shape, wherein the rotatable radio transmission structure is comprised of a pair of parallel spaced metal discs supported within the sphere, said spaced plates being of a greater radial extent than the sphere segment in which they are positioned and project to outside of the sphere.

8. A transmitter antenna of the character described comprising a radio wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying signal energy about a 360 segment of said lens and means for applying radio signal energy to said radio transmission structure whereby a 360 radiation pattern is transmitted about said lens, said 360 segment being in a horizontal plane, producing a horizontal radiation pattern centered about said zenith, wherein the rotatable radio transmission structure is comprised of a pair of opposed metallic plates supported within the lens, said opposed plates being in the form of a cone.

9. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported within said lens for applying signal energy about a 360 segment of the lens, motor means for continuously rotating said transmission structure, means for applying radio signal energy to said interior rotatable radio transmission structure, and means altering the said basic dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher altitude angles.

10. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported Within said lens for applying signal energy about a 360 segment of the lens,

motor means for continuously rotating said transmission structure, means for applying radio signal energy to said interior rotatable radio transmission structure, and means altering the said basic dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher altitude angles, wherein the said specific region is in an inverted conical shape with its apex near the lens center and its base intersecting the zenith, and composed of dielectric material of greater dielectric constant than that of the lens ma terial surrounding the region.

11. A transmitter antenna of the character described comprising a radio wave lens extending symmetrically for 360 about its zenith and composed essentially of dielectric material varying radially in descending dielectric constant, a symmetrical generally horizontal rotatable radio transmission structure supported within said lens for applying signal energy about a 360 segment of the lens, motor means for continuously rotating said transmission structure, means for applying radio signal energy to said interior rotatable radio transmission structure, and means altering the said basic dielectric constant arrangement of the lens along a specific region thereof to emphasize the radiated pattern strength at the higher altitude angles, wherein the said specific region is in an inverted conical shape with its apex near the lens center and its base intersecting the zenith, and composed of dielectric material of reater dielectric constant than that of the lens material surrounding the region, further including a second conical region arranged mirror-symmetrically below said specific region and composed of dielectric material of smaller dielectric constant than that of the lens material surrounding it.

12. A transmitter antenna of the character described comprising a radio Wave lens extending for 360 about its zenith, a rotatable radio transmission structure for applying signal energy about a 360 segment of said lens and means for applying radio signal energy to said radio transmission structure whereby a 360 radiation pattern is transmitted about said lens, said 360 segment being in a horizontal plane, producing a horizontal radiation pattern centered about said zenith, wherein the rotatable radio transmission structure is comprised of a pair of opposed metallic plates supported within the lens, said spaced plates being of a greater radial extent than the sphere segment in which they are positioned and project to outside the sphere, said means for applying radio signal energy to said opposed metal plates comprising a coaxial transmission line arranged along the zenith diameter of the lens and secured to the central region of said plates through a matching transformer, further including an extension of said coaxial transmission line along the zenith diameter above the metal plates to counterbalance the presence of the coaxial transmission line in the lens.

References Cited by the Examiner UNITED STATES PATENTS 2,576,181 11/51 Jams 343-754 2,881,431 4/ 59 Hennessly 343-753 2,945,228 7/60 Ramsay et al. 343753 2,978,702 4/61 Pakan 343909 X HERMAN KARL SAALBACH, Primary Examiner. 

2. A TRANSMITTER ANTENNA OF THE CHARACTER DESCRIBED COMPRISING A RADIO WAVE LENS EXTENDING FOR 360* ABOUT ITS ZENITH, A ROTATABLE RADIO TRANSMISSION STRUCTURE FOR APPLYING IMPRESSED SIGNAL ENERGY ABOUT A 360* SEGMENT OF SAID LENS, MOTOR MEANS FOR CONTINUOUSLY ROTATING SAID TRANSMISSION STRUCTURE, AND MEANS ELECTRICALLY COUPLED TO SAID RADIO TRANSMISSION STRUCTURE FOR APPLYING RADIO SIGNAL ENERGY THERETO TO EFFECT A 360* RADIATION PATTERN OF TRANSMISSION OF THE SIGNAL ENERGY ABOUT SAID LENS, THE 360* SEGMENT BEING SUBSTANTIALLY IN A HORIZONTAL PLANE AND THE ROTATABLE RADIO TRANSMISSION STRUCTURE BEING COMPRISED OF A PAIR OF OPPOSED METALLIC PLATES SUPPORTED WITHIN THE LENS AND THE OPPOSED PLATES ARE IN THE FORM OF CONES. 